A pectineal line is a slender bony ridge or thin line of raised bone that is located in two places within the human body. One of the ridge marks, called the femoral pectineal line, is found along the side of the upper part of the femur bone, also called thighbone. The other elevated line, the pectin pubis, is positioned on the flat portion of the pubic bone known as the superior ramus. Both of the pectineal lines are connected to each other by a flat rectangle of muscle called the pectineus muscle, a strong inner thigh muscle responsible for the flexion of the hip.
An elevated bony ridge that forms the femoral pectineal line is also called the intermediate ridge of the femur. It begins on the femur bone at the lesser trochanter, a bony bump located directly underneath the backside of the femur neck, and continues on to a section of the posterior part of the femur bone called the linea aspera. The bony ridge of the linea aspera is where many of the large thigh muscles, including the adductor magnus, adductor brevis, and adductor longus, are attached to the femur bone. This femoral pectineal line extends from the lesser trochanter to about one quarter of the length of the femur bone before transitioning into the linea aspera.
The pectineal line of the pubis, also known as the pectin pubis, is located just above the obdurator foramens, which are the two small openings created by the pelvic bones located on the lower portion of the skeletal structure. An elevated bony line across the top of the superior pubic ramus bone, which forms the upper portion of the obdurator foramen, is the pectineal line of the pubis from which the pectineus muscle originates. The pectineus muscle travels between the tubercle protrusion on the pubic bone and the iliopectineal eminence, which is the anatomical junction of the pubic bone and the large ilium bone of the pelvis.
Another function of the pectineal line of the pubis is to form part of the iliopectineal line on the pelvic bone. When the pectineal line joins with the arcuate line that begins on the inferior side of the ilium bone, it forms the division line separating the pelvis major and the pelvis minor that is called the iliopectineal line. The anatomical distinction between the pelvis major and pelvis minor is useful when identifying and diagnosing abnormalities of the pelvic region.